Prokaryotes and gram staining

Prokaryotes

Organsims that lack membrane-bound organelles.

What are the two types of prokaryotes that make up 2 of 3 domains of life?

Bacteria and Archaea

What is the 3rd domain of life and what does it encompass?

Eukarya; it encompasses other organisms such as protists, fungi, plants, and animals.

Where can archaeans be found?

in every environments as they can handle extreme temperatures.

What do bacteria lack?

membrane-bound organelles

Cyanobacteria

A major group of bacteria that grow in various environments (ex. freshwater, marine, and terrestrial habitats)

what are some of the ecological functions cyanobacteria provide

producing oxygen, fixing carbon dioxide out of the atmosphere, provide a food source for invertebrates, and act as an indicator of water quality

What is one cause of cyanobacterial blooms?

high nutrient levels

Name 3 groups of cyanobacteria.

Anabaena, Merismopedia, and Oscillatoria.

Where is Anabaena found?

Freshwater, saltwater, hotsprings, and top-soil

What does anabaena form during periods of nitrogen limitation?

Heterocysts

What are heterocysts?

specialized cells in anabaena that fix nitrogren. can aslo turn N2 gas into nitrogen compounds that the cell can use.

What are akinetes?

dormant (resting state) cells

What traits do akinetes possess?

Tougher than normal vegetative cells and resistant to cold and drying out

Where is Oscillatoria found?

fresh water, saltwater, and hot springs

Why do colonies slide back and forth against each other?

to orient to a light source

Where is Merismopedia found?

a variety of aquatic habitatas and freshwater sediments

what shapes do merismopedia colonies form?

grid-like sheets

What groups of cyanobacteria are filamenous?

Anabaena and Oscillatoria

What cyanobacteria is this?

Anabaena

What cyanobacteria is this?

Oscillateria

What cyanobacteria is this?

Merismopedia

Gram Staining

a differential stain which distinguishes bacteria based on cell wall composition

what color is gram positive bacteria?

purple

what color is gram negative bacteria?

pink

what is the result of this gram stain?

gram positive bacteria

what is the result of this gram stain?

gram negative bacteria

what is the first step of gram staining?

heat fixation

how do you fixate bacteria?

heat via bunson burner

whats the second step in gram staining?

staining the slide with crystal violet

what does crystal violet do?

stains all bacterial cells purple

what is the 3rd step in gram staining?

adding an iodine solution

what does iodine do?

fixes the crystal violet dye to the cell walls of bacteria

what is the fouth step of gram staining?

adding alcohol solution

what does alcohol do?

washes off the gram negative cells

what is the fifth step of gram staining?

safranin

what does safranin do?

acts as a counterstain to make gram negative cells visible.